1. Field of the Invention
The present invention relates to an apparatus and a method of thermal transfer recording to record image on a recording medium by transferring ink of the ink sheet on the recording medium.
Here, the thermal transfer recording apparatus includes, facsimile machines, electronic typewriters, copying machines and printers, etc.
2. Related Background Art
Generally speaking, a thermal transfer printer records the image by using an ink sheet obtained by coating heat-meltably (or heat-sublimable, etc.) ink on a base film, heating such ink sheet by the thermal head selectively responding to the image signal and transferring the molten (or sublimated, etc.) ink on to the recording sheet. Since this ink sheet is generally of such type that by one image recording, the ink is completely transferred to the recording sheet (the so-called one-time ink sheet), it was necessary that when recording of one character or one line is over, the ink sheet should be conveyed for the length corresponding to the recorded length so that an unused part of the ink sheet comes to the succeeding recording position with certainty. As the result, the amount of use of the ink sheet increases, and the running cost of thermal transfer printer tends to become high.
In order to solve such problem, they proposed the thermal transfer printer wherein the recording sheet and the ink sheet are conveyed at somewhat different speed as described in Japanese Laid-Open Patent Application No. 57-83471, Japanese Laid-Open Patent Application No. 58-201686 or Japanese Patent Publication No. 62-58917. As described in the references an ink sheet on which image may be recorded plural number of times (the so-called multiprint ink sheet) has been made available and if such ink sheet is used, it is possible to record the image by conveying the ink sheet after completion of recording or during recording of the image for the length smaller than the recording length L (L/n, N&gt;i) at the continuous recording of recording length L. By so doing, the efficiency of use of the ink sheet becomes n times higher than the conventional way of use and thus reduction of running cost of thermal transfer printer can be expected. Hereafter this recording system is called multi-print system.
In the case of the thermal transfer printer which performs such multi-print, moving speed of ink sheet is slower than the moving speed of recording sheet and therefore due to the abrasion between the ink sheet and recording sheet such problem occurs as wrinkling or slackening of the ink sheet. While with this type of printer, it is normal that the equipment is provided with a cutter to cut the recorded sheet in one page length and particularly with the facsimile equipment, it is desirable to have a cutter which cuts the recorded sheet in one page length. However when such cutter is provided, it tends to require conveying of recording sheet in such way that at the completion of recording of one page of recording sheet, the sheet is conveyed in the direction of cutter until the rear edge of the recorded image passes by the position of cutter for the distance inclusive of the margin (the so-called front feed) or after the cutting of the recorded sheet by the cutter, the point near the front edge of the recording sheet is returned to the recording position of thermal head (the so-called back feed).